Reintroduce type parameter lost in the rewrite for Email::Sender.

[racke]

Proposed fix for the following GitHub issue:

#10

Regards
Racke

[racke]

Note: MIME::Entity doesn't seem to support Format 'flowed'.

Regards
Racke

[ironcamel]

I used part of your patch to add support for html and plain text emails. I have not yet added support for type 'multi'. Take a look: 1e66a34

[ironcamel]

I added a line:

    $headers{Format} ||= 'flowed' if $headers{Type} eq 'text/plain';

I noticed that you said MIME::Entity does not support Format 'flowed'. I am assuming that MIME::Entity would just pass that header on to the client and it is the job of the client to support format flowed or not. I'm not sure how exactly to test format 'flowed', but leaving that line at least does not seem to break anything.